Imagine There Is a Forest with 2000 Trees, and We

Multiple Choice

Imagine there is a forest with 2000 trees, and we want to know the average height. Which of the following is the best procedure to generate an unbiased sample of size 50?

A) Measure all the heights and then choose the 50 with the heights closest to the average.
B) Measure the 50 trees closest to the center of the forest.
C) Number all the tree, randomly generate 50 numbers between 1 and 2000, and measure those trees.
D) Number all the trees, then starting with the first tree, measure each 2000/50 = 40th tree.